The present invention relates to an improved method of producing a discarding sabot projectile in which the individual sabot segments are secured and sealed against one another in a vulcanizing tool including an injection mold in that a thin layer or coating of caoutchouc or rubber is sprayed onto the rear gas pressure receiving surface of the discardable sabot and is vulcanized. The invention also relates to the discarding sabot projectile produced according to this method.
Federal Republic of Germany DE-OS 1,703,507 corresponding to U.S. Pat. No. 3,620,167 discloses a subcaliber, fin-stabilized discarding sabot projectile in which the sabot includes a sealing coating of vulcanized rubber synthetic or of caoutchouc (natural rubber) which is applied to the rear gas pressure receiving surface. For the application and vulcanization of the sealing covering, the discarding sabot projectile is placed into a vulcanizing tool provided with an appropriate injection mold. The injection mold leaves a thin circular disc shaped cavity at the rear gas pressure receiving surface of the sabot for the heated sealing material which is injected in liquid form and, when the liquid material is injected, seals the rear outer circumference of the sabot and the projectile body over its circumference at an appropriate distance (e.g. 3 to 8 mm) from the rear gas pressure receiving surface of the sabot. The sealing coating, on the one hand, fixes or secures the segments of the sabot in their rear region and seals the parting grooves of the sabot segments against the gas pressure of the propelling charge gases.
The liquid sealing mass is injected into the injection mold under a high pressure of, for example 1000 to 1500 bar, usually through a laterally disposed fill opening. Thereafter, the discarding sabot projectile remains in the injection mold or in the vulcanizing tool for a period of about 10 to 15 minutes at the appropriate temperature of, e.g., 150.degree. C. to completely vulcanize, i.e., to solidify, the rubber substance.
Since a seal of the contact faces of the individual elements (discarding sabot segments, projectile body, injection mold components) can practically never be realized one hundred percent because of the permitted or unavoidable dimensional tolerances, it may happen during injection of the rubber mass that the liquid material, which is injected at high pressure, penetrates in an uncontrolled manner into the possibly existing thin gaps between the components and becomes visible as a thin rubber skin (e.g. of a thickness less than 0.1 mm) when the discarding sabot projectile is removed from the vulcanizing tool. This skin can easily be pulled off and removed in the outer regions, i.e., in the areas of contact between the injection mold and the outer circumference of the projectile or the outer circumference of the discarding sabot. However, this is not possible in the inner cylindrical annular gap or annulus between the sabot segments and the projectile body. Since the liquid material may have penetrated to irregular depths, depending on the width of the gap and the injection pressure, this may have disadvantageous effects with respect to true dimensions and in connection with the release of the discarding sabot segments from the projectile body after firing (or, more precisely, when the projectile leaves the muzzle of the gun barrel), resulting in irregular release of the sabot segments and a reduced hit accuracy.